In page.tpl.php
the content of the page is available in $page['content']
. It seems that your are mixing two different concepts here: pages, any page on the site (including administration page, taxonomy terms page, and other not directly editable pages) and nodes, editable content. This can be rather confusing as a default Drupal installation provides a page content type. So you end up with page nodes, which are nodes of a the page content type.
The layout of the content of a page displaying a node, is handled in the node.tpl.php
template. In this template, the body of the displayed node is available in $content['body']
.
If you really need to access a field (handled using the Field API) of the node object ($node
) from the page preprocess function in your template.php, you can use:
function THEME_preprocess_page(&$variables) {
$node =& $variables['node'];
$value = field_get_items('node', $node, 'FIELDNAME);
}